As a high-performance permanent magnet, there have been known rare-earth magnets such as a Sm—Co based magnet and a Nd—Fe—B based magnet. When a permanent magnet is used for a motor of a hybrid electric vehicle (HEV) or an electric vehicle (EV), the permanent magnet is required to have heat resistance. In a motor for HEV or EV, a permanent magnet whose heat resistance is enhanced by Dy substituting for part of Nd of the Nd—Fe—B based magnet is used. Since Dy is one of rare elements, there is a demand for a permanent magnet not using Dy. As a motor and a power generator with high efficiency, a variable magnetic flux motor and a variable magnetic flux power generator using a variable magnet and a stationary magnet are known. In order to improve performance and efficiency of the variable magnetic flux motor and the variable magnetic flux power generator, there is a demand for improvement in a coercive force and magnetic flux density of the variable magnet and the stationary magnet.
It is known that, because the Sm—Co based magnet has a high Curie temperature, it exhibits excellent heat resistance without using Dy and is capable of realizing a good motor characteristic and so on at high temperatures. A Sm2Co17 type magnet among the Sm—Co based magnets is usable as a variable magnet owing to its coercive force exhibiting mechanism and so on. Improvement in coercive force and magnetic flux density is also required of the Sm—Co based magnet. In order to increase magnetic flux density of the Sm—Co based magnet, it is effective to increase Fe concentration, but the coercive force tends to decrease in a composition range where the Fe concentration is high. Under such circumstances, there is a demand for a technique for making a Sm—Co based magnet having a high Fe concentration exhibit a high coercive force.